Stabilization of insertion electrodes for lithium batteries

This paper discusses the techniques that are being employed to stabilize LiMn 2O 4 spinel and composite Li x MnO 2 positive electrodes. The critical role that spinel domains play in stabilizing these electrodes for operation at both 4 V and 3 V is highlighted. The concept of using an intermetallic electrode MM′ where M is an active alloying element and M′ is an inactive element (or elements) is proposed as an alternative negative electrode (to carbon) for lithium-ion cells. An analogy to metal oxide insertion electrodes, such as MnO 2, in which Mn is the electrochemically active ion and O is the inactive ion, is made. Performance data are given for the copper–tin electrode system, which includes the intermetallic phases eta-Cu 6Sn 5 and Li 2CuSn.